Butterfly,
The way to forgive yourself is to make amends and to never let it happen again. Some have mentioned the Steps. Others may think of a priest or a minister to confess to, in order to gain forgiveness, which will lead to self forgiving. Someone did mention G*D's forgiveness.
There is no concept of "sin" in Judaism. What Christians call "sin" we call "missing the mark." Think of it as an archer, who misses the target, ok? What does the archer do? They try again. And they keep trying, until they get it right; until they hit the bulls eye. Teshuva, turning around, is what we do. When we miss the mark, we turn around and try again, until we hit that bulls eye. Then, we are living as G*D wants us to live.
Many believe that confession to another person heals the soul. That's what therapy is about. That's what sponsors are for too, in a 12 Step program. Or a priest/minister in Christianity. But, you can confess to G*D. Make it real; promise to make teshuva -- to turn around. And keep trying until you are capable of never ever doing the same type of thing again. Then, you are in G*D's grace. Then, there is the peace of self forgiveness.
G*D loves you, Butterfly. And so do we.
You are a strong woman.
Shalom!